MongoDB Aggregation Framework Group Query Example

ตัวอย่าง Aggregation Framework ด้วย $group

สำหรับการนี้ ให้ใช้ $group ใน MongoDB Aggregation

สร้าง Collection พร้อมข้อมูล

> db.demo639.insertOne(
...     {
...         "_id" : 1,
...         "CountryName" : "US",
...         "Info1" : {
...             "Name" : "Chris",
...             "SubjectName" : "MySQL",
...             "Marks" : 78
...         },
...         "Info2" : {
...             "Name" : "Chris",
...             "SubjectName" : "MySQL",
...             "Marks" : 78
...         }
...     }
... );
{ "acknowledged" : true, "insertedId" : 1 }
> db.demo639.insertOne(
...     {
...         "_id" : 2,
...         "CountryName" : "UK",
...         "Info1" : {
...             "Name" : "Chris",
...             "SubjectName" : "MySQL",
...             "Marks" : 79
...         },
...         "Info2" : {
...             "Name" : "Chris",
...             "SubjectName" : "MySQL",
...             "Marks" : 88
...         }
...     }
... );
{ "acknowledged" : true, "insertedId" : 2 }

แสดงเอกสารทั้งหมด

> db.demo639.find();

ผลลัพธ์:

{ "_id" : 1, "CountryName" : "US", "Info1" : { "Name" : "Chris", "SubjectName" : "MySQL", "Marks" : 78 }, "Info2" : { "Name" : "Chris", "SubjectName" : "MySQL", "Marks" : 78 } }
{ "_id" : 2, "CountryName" : "UK", "Info1" : { "Name" : "Chris", "SubjectName" : "MySQL", "Marks" : 79 }, "Info2" : { "Name" : "Chris", "SubjectName" : "MySQL", "Marks" : 88 } }

คิวรี Aggregation $group

> db.demo639.aggregate({$group : {_id : {Name1:"$Info1.Name",Name2:"$Info2.Name"},
...     Marks:{$first:"$Info2.Marks"},
...     Marks:{$sum:"$Info2.Marks"}
... }}).pretty();

ผลลัพธ์:

{ "_id" : { "Name1" : "Chris", "Name2" : "Chris" }, "Marks" : 166 }